Many long producing formations such as for example in open hole use a series of screen sections. In a long horizontal run the screen nearest the heel or the surface will be a path of least resistance as compared to other screen sections further into the horizontal run. The same is true for deviated and even vertical subterranean formations. To compensate for this short circuiting in the horizontal run screen sections have been assembled into a string where the base pipes are not perforated but provide a series of flow channels to a static flow control device such as a spiral restricted path. The spirals in different sections offer different resistance so as to balance the flow through the various screen sections regardless of whether the flow is in from the formation or out in injection service. The assembly is illustrated in U.S. Pat. No. 6,622,794. Related references to this concept are U.S. Pat. Nos. 7,467,665; 7,409,999 and 7,290,606.
While balancing flow among discrete spaced apart screen sections is accomplished with the spiral paths that offer to balance the flow through the assortment of screen assemblies, the flow patterns in each screen section are virtually unaffected in a given screen section that can be about 10 meters long. The present invention attempts to address this issue at a given screen section by providing a screen structure that compensates for what would otherwise be flows driven by the paths of least resistance and that would leave more of the flow moving at a high velocity through the screen at the location of an inflow control device closest to the surface. The higher velocities at the shorter paths to the surface even with inflow control devices have caused damage to screens from erosion and have caused undesirable production of water or particulates. The present invention provides varying resistance to flow in a given screen section in several ways. By way of example, the number of openings of a given size in a given subsection can vary along the length of a screen. Alternatively identical screens can be overlapped in discrete portions of a screen length. Alternatively, the density of openings of a given size can vary along the length of a given screen section to balance flow through it. The wire wrap cross-section that underlies a screen can be reconfigured from the known triangular cross-section to a different shape that is more toward trapezoidal so that less turbulence is created on entry toward the base pipe to reduce the overall flow resistance in a given section of screen. Those skilled in the art will better appreciate the invention from a review of the description of the preferred embodiment and the associated drawings while realizing that the full scope of the invention is given by the appended claims.